n = int(input())
seen = set()
ans = 0
for _ in range(n):
    a, b, c = map(int, input().split())
    if a in seen:
        ans += 1
        seen.remove(a)
    else:
        seen.add(a)
    if b in seen:
        ans += 1
        seen.remove(b)
    else:
        seen.add(b)
    if c in seen:
        ans += 1
        seen.remove(c)
    else:
        seen.add(c)
ans += len(seen) // 4
print(ans)